The article reviews various aspects of the origin of the motives that cause states to cooperate with each other, which was enshrined in the Charter of the United Nations as the jus cogens generalis fundamental principle of international law. An attempt is being made to prove the intrinsic nature of interaction between countries in resolving pressing problems of international security and ensuring a world order worthy of the high level of development of humanity at the present stage of its existence. A brief overview of the doctrinal views of renowned scholars on interstate relations and their international legal regulation is provided. The activities of interstate integration associations are analyzed using BRICS as an example.